This study is to determine if elderly people exposed to fine particles normally present in the outdoor air react by undergoing transient changes in their lungs or heart. Changes in the lung will be measured by testing the ability to blow through a plastic tube before and after exposure to particles. The heart will also be monitered before, during, and for several hours after exposure for any changes that may occur. Although the level of particles the patients will be exposed to will be higher than might normally be found in Chapel Hill, they will not be higher than in major US cities such as Los Angeles or New York.